Numerical Study of Consolidation Effect on the Response of Passive Piles Adjacent to Surcharge Load

Abstract

Piles subject to soil lateral movement are often referred to as passive piles. The response of passive piles in clayey soils adjacent to surcharge is not only dependent on the soil intrinsic behavior but also on the loading schedule and consolidation situation. In this study, the effect of consolidation on the behavior of a 2 × 2 pile foundation involved in a warehouse collapse in 1998 in Shanghai, China, was investigated. An experimental study on passive piles in Shanghai soft clay subject to incremental surcharge loading was reviewed. Then, numerical modeling was conducted using two-dimensional (2D) finite-element (FE) models with two different pile–soil interaction methods: embedded and link-element methods. The FE models were validated against the in situ passive-pile test, and then a parametric study on the rate of loading was conducted. The responses of passive piles to fast loading (e.g., linearly applied 120 kPa in 30 days) and staged loading were compared. The former corresponds to the working condition of the collapsed industrial warehouse, and the latter corresponds to the loading schedule of the field experiment. The results show that the displacement of the pile top under the condition of 1-month fast loading was approximately 1.4 times that of the staged loading. The proportion of immediate displacement was also studied with FE modeling. The load transfer between soil and pile and the consolidation process were also investigated.